


Learning Curve

by phdJohnlock



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: F/M, Kissing, Plot What Plot/Porn Without Plot, Pre-Time Skip, Premature Ejaculation, it should be assumed that everyone in this fic is a consenting adult
Language: English
Status: Completed
Published: 2020-04-05
Updated: 2020-04-05
Packaged: 2021-02-26 16:42:12
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,148
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23469244
Author URL: https://archiveofourown.org/users/phdJohnlock/pseuds/phdJohnlock
Summary: Every risk Felix took was calculated, except one.
Relationships: Felix Hugo Fraldarius/My Unit | Byleth
Comments: 4
Kudos: 50





	Learning Curve

**Author's Note:**

> Hi! Don't read this if you don't want to read teacher/student stuff. I have not leaned into that dynamic here but this takes place pre-time skip. Felix is a student and Byleth is his professor. Also, I googled Felix's age during the first half of the game and then I decided he had a birthday, so he's 18 now, and that's legal in all three countries baybeeeeee. I also shoehorned that fact into the text under the assumption that people would skip this note, you're welcome.
> 
> My grammarly browser extension tells me the tone of this note is informative, confident, and friendly. I hope you feel properly informed.

Felix was not a foolhardy man. Sylvain may have ribbed him about recklessness on the battlefield, but every risk Felix took was calculated. Claude didn’t trust him to help plan tactical approaches because, he said, Felix wanted to stab first and think never. The first time Claude tried to tactfully deny his input, Felix scoffed and left the room. He didn’t need to plan in order to beat their enemies in battle. He was just _better_. He knew when he could feint and draw a bandit off balance, as well as when to retreat and signal for an ally on wings to swoop in and take care of a problem for him. 

Although he had initially harbored some doubts about the wisdom of transferring into the Golden Deer house, primarily rooted in his uncertainty about whether anyone left in the Blue Lions could tame Dimitri when he inevitably lost it, he could not miss the chance to train with a real professional. Hanneman knew a lot about magic, and had even taught him something about his crest, but the man had no skill in swords. His gamble was rewarded almost immediately when Byleth agreed to spar with him on a weekly basis. Her swordplay was exceptional, so sharp and precise he hardly ever found an opening when she didn’t deliberately provide one. He’d never think about Hanneman’s dry lecturing again.

In battle with his new classmates, Felix found himself rewarded again and again when his training paid off. Their teamwork left something to be desired, but he was learning to sneak off on his own, take down a high-value target, and return to front lines with nary a scratch on him. With each dangerous maneuver, he felt Byleth’s watchful eyes on him, making sure she didn’t need to pull him away from a mess. She never needed to.

Lessons with Byleth were something else altogether. She was serious while she lectured, drilling into their heads the advantages and disadvantages of battalion formations and the tactical reasons they would make any number of choices on the battlefield. Felix didn’t know how she had learned these things, but it was clear she knew fighting like the back of her hand. In group skirmishes, mistakes were not tolerated. Byleth often said poor decision making on the battlefield was a surefire path to death, and she emphasized - repeatedly - that distractions did not belong within a thousand feet of anywhere they needed to use their weapons. Her eyes would often flick to, and then away from, Felix when she said this.

It took him a very long time to figure out why.

They didn’t really know much at all about her. Claude had figured out her birthday, and she talked to Mercedes sometimes about her childhood - everyone talked to Mercedes about things like that. Ignatz said she liked art, while Hilda argued that she just liked that he liked it. Lorenz called her uncouth; Sylvain called him a shithead, but only behind his back. Bernadetta once offered that she was a really good cook, and Ashe agreed. Felix knew that when she smiled, she had a dimple on her left cheek.

He didn’t share that with the others.

Every risk Felix took was calculated, except one.

Byleth stepped around him, feet barely seeming to touch the ground as she knocked his practice sword around like a toy. He was flustered, trying to keep his cool and wait for her to make a mistake. The problem was that she never made mistakes, and she knew his style too well at this point. He parried a split second too late, and she had him.

“I yield!” Felix uttered, out of breath. Byleth’s sword edge was against his throat and her other forearm pressed across his chest to flatten him to the wall. She stared at him for a long moment more before she smiled and pulled the sword away, throwing it to the ground. 

As she leaned back and began to pull her arm back, Felix reached up to grab her bicep. He hadn’t really thought this through, had no plan to go on. It was like his body had a mission his brain didn’t have the clearance for.

Confusion showed on her face as she looked down to where his hand wrapped around her arm. His long fingers nearly encircled her whole arm, muscular as she was.

“Are you… okay?” she asked. This was unusual, especially for Felix, unless he was somehow going to try to prolong the fight without weapons. He was looking at her strangely, his peculiar amber eyes wary on her face. His lips were parted slightly and his hair had come partway undone from its usual ponytail, falling in messy pieces around his face. Though she tried not to think of the students in terms of their attractiveness, they were contemporaries in age, and she didn’t feel too badly about it - she found Felix to be very handsome, especially at times like this. She frequently found herself watching him, just to see how he moved. But she’d never been this close to him for so long, as he tended to be rather prickly at any suggestion of closeness.

Felix swallowed once before speaking. If she didn’t know any better, she would think he was trying to muster up courage.

“How old are you?” He asked it with a snap, more forcefully than such an innocent question really warranted.

The question took her by surprise. “I don’t know. Why does that matter? Is everything okay, Felix?”

His grip on her arm tightened. “Why don’t you know? Who doesn’t know how old they are?” Byleth had to stop herself from rolling her eyes. She could not keep having this conversation.

“My father never kept track of my birthday, I don’t know what you want me to say. Why does it matter?”

“I just - you aren’t that much older than me, right? Than all of us here?” Felix asked. He continued to hold her arm, but his gaze flicked down to her mouth momentarily. She was panting slightly, still out of breath from their round of sparring. Where her hand was now pressed against his chest, Byleth could feel him breathing heavily as well. The atmosphere between them was charged.

“How old are you? I don’t think I’m much older than any of you. Some of the students are probably older than me.”

Felix relaxed his grip on her arm, just slightly. He said, “I’m eighteen.” Then he took a shaky breath in. In a low voice, he added, “I just wanted to know if I could do this.” Suddenly, he pulled her forward and pressed his lips to hers.

For just a moment, Byleth stiffened, and Felix pulled back immediately. But before he could say anything, Byleth pushed into him and kissed back. His movements were uncertain, but eager, and hers equally so. She grabbed the front of his shirt, prompting him to gasp slightly. Felix released her arm, only to form his palm against the back of her neck, cradling the base of her skull and snaking his fingers up into her hair. He pulled Byleth’s body against his own and she sank into him, moaning softly into the kiss. His tongue pressed into her mouth and she met it, tentatively at first, but then with increased fervor as they both began to move.

Felix moved his lips against hers, licking into her and savoring the small noises she made. Desire pricked under his skin like lightning, licking down his spine and pooling in his groin. Her scent was intoxicating and heady, and he didn’t have the brainpower available to figure out how that could be when they’d just finished a workout.

Byleth pressed Felix’s body into the wall, writhing slightly, thoroughly enjoying the feeling of his hand in her hair and the other pressed against the small of her back. She moved her own hands to frame his angular jaw. She cupped his face and kissed him eagerly, her heart pounding in her ears. His slick lips slid against her own over and over again. Her knees felt like rubber, and she was thankful for his arm around her waist keeping her upright.

Felix broke away, leaving Byleth panting, but he didn’t move far. He pressed a kiss to the corner of her mouth, then one just below her ear, and trailed small kisses down the side of her neck. At the juncture where her neck and shoulder met, he placed an open-mouthed kiss, licking at her skin before pressing his teeth gently to the skin as if experimenting. Byleth let out a small sound that she hardly had control over, which he seemed to take as encouragement. He bit down just slightly, then kissed his way back up to her mouth. Byleth’s head lolled back into his hand. She focused on the sensations of his lips against her skin, not thinking about anything else, forgetting entirely where they were.

Felix stilled his lips and pressed them to her forehead. He muttered, “Sorry,” and Byleth huffed out a laugh.

“Sorry for what,” she asked, her voice huskier than she intended. Felix pulled back to stare at her. His eyes were dark pools; she wanted to fall into them, into him, and never come back out. She licked her lips; Felix’s eyes followed her tongue, and then he chased it with his mouth. He licked along her bottom lip and then captured it in his teeth, a slight pain that drew another groan from deep within Byleth’s throat. He released her and pressed another open-mouthed kiss to her lips, then pulled back away. Byleth remained in the position he left her, head tilted slightly back, lips parted, gazing up at him. She pressed him into the wall with her whole front, and he suddenly wondered quite seriously whether she could tell how aroused he was. 

“Sorry… uh, for doing that without asking,” he murmured, and she laughed slightly. To both his chagrin and his relief, she took a step backward to put a more respectable distance between them. She tilted her head to the side but glanced up at him, coy. On the side of her neck, he saw a slight red mark where his teeth had been. He felt dizzy with lust.

“I didn’t mind,” she replied honestly. “But why do you care how old I am? Does that matter?”

Felix didn’t know what to do with his hands, so he clenched them into fists at his sides and released them. He said, “I’m not… experienced. I didn’t want… it’s not that you’re the professor, or anything, since I technically outrank you in status, but. I didn’t want to be. Embarrassed.” 

“I wouldn’t know the difference,” Byleth replied easily. “There isn’t much time for romance in mercenary life.” She studied his face before adding, “But I don’t want to make you uncomfortable. I don’t know what the rules are for, you know, students. And me.”

Felix scoffed. “I don’t care what the rules are. They think I can’t make my own decisions? I’d like to see them stop me.” 

Byleth laughed, a rare sound. Felix wanted to commit to memory, to hear it in his dreams. 

“What do you want, then?” she asked. 

“This,” Felix said, immediately. Then, “More.” 

Several days passed before Felix found himself in Byleth’s room, late at night. He stood just inside the door, a bit unsure of his place. He’d snuck down the stairs, he thought, with no one noticing. All that stealth training was paying off.

Byleth wore a nightgown, which he’d obviously never seen her in before, and he was already excited, though he tried not to let it show. He looked around a bit, trying to land on a good topic for small talk. “How are you?” he asked, then grimaced. “No, that was stupid. I don’t know why I said that.” 

She smiled and tossed her hair to one side. “It wasn’t stupid, Felix, you can be polite. But we don’t need to small talk if you don’t want. Come here.” 

He crossed the room to stand in front of her. Hesitantly, he reached out his hand, and she tangled her fingers in his. The contact sent shivers down his spine, which was absurd. 

“What do you want?” Byleth asked.

Never had such a simple question been so difficult to answer.

“I want… I don’t know.” Felix frowned. Why didn’t he know? It was like she stole the thoughts from his head; he could hardly think around her. 

“Haven’t you thought about it?” Her eyes sparkled, and she must have been teasing, but what a ridiculous thing to say.

“Of course I’ve thought about it,” Felix snapped, feeling his cheeks flush. “It’s all I’ve thought about. It’s interfering with my training.” 

Byleth laughed, and squeezed his fingers. She said, “I’ve been thinking about it too. Like I said, I don’t know what I’m doing any more than you do. But I want…” She looked down, and with a start, Felix realized she was being _shy_. Byleth was the least shy person he knew. “I want to hear you say it,” she finished in a rush. 

“Oh,” Felix sighed, feeling a rush of arousal. “Okay.” He swallowed and shifted his weight foot to foot; she glanced up at him and he was emboldened. “I want to. Touch you. I really want to pull that little dress off you. I want you to touch me. Do you… want -”

Byleth interrupted him by pushing toward him and capturing his lips in a kiss. “Yes,” she sighed, “I want that. Please touch me.” She raked her hands up his back, dragging her chest against him. 

Felix felt a dam break within him. He wanted _her_.

Felix pushed her backward until they hit the bed, kissing her along the way. He held her waist in his hands, felt the muscles of her core work as she bent to accommodate his kisses. The thin nightgown did little to shield her from the cold, he thought, but did far, far too much to separate his skin from hers. Carefully, he guided her backward down onto the bed and followed, propping himself up on one elbow. She was splayed beneath him, her hair fanned out on the pillow, her lips plump and wet from his kisses. Hoping she wouldn’t see, he used his free hand to adjust his cock, which was hard in his sleep pants. She did see, of course, and smiled wickedly.

Before she could comment, Felix claimed her mouth with another kiss. He pressed his hand to her cheek, holding her tenderly for just a moment, before stroking down her arm. He wanted so badly to feel her bare skin, to cup her ample breasts in his hands and feel their soft weight, but he hesitated. As if reading his mind, Byleth took his hand in hers. She smiled into his lips and moved his hand, placing it against her breast. He immediately squeezed, eagerly palming as much as he could, and then rubbed his palm across her hardening nipple. She gasped in a breath, and he pulled back to watch her face. Her eyes had fallen closed; she pushed her chest upward toward his hand, chasing the contact. He leaned forward to press his face to her chest, silently cursing the fabric that was still in his way. 

“Does that feel good,” he murmured into her sternum, pushing his nose into the soft mounds of her. He passed his thumb over her tight peak, very evident even through her nightgown, and she keened in response. He did it again, and again, savoring the sounds she made. He wanted to consume those sounds, swallow them down and make them part of himself. He sat up, just slightly, and repositioned himself above her, hands on either side of her head. He gazed down at her, the pink high on her cheeks, her eyes lidded. 

Without saying anything, Byleth wrapped one leg around his waist, and then the other. Felix sucked in a breath, momentarily overwhelmed by the feeling of her pressed against his hard cock. He shifted his weight to one hand, bringing the other up to the outside of her thigh. Her skin was so soft. Slowly, exercising all his self-control, he ran his hand up her leg to her hip. He squeezed, savoring the sound Byleth made in response, and slowly dragged his fingernails across her skin. She wiggled her hips at the sensation and he moaned, too loudly, at the movement against his cock.

It was then that Felix glanced down and realized that Byleth was not wearing anything under her nightgown, and that her naked skin was pressed against him, and he could see… everything. 

“Oh,” he gasped, and he pressed his face into her neck, completely overwhelmed. He bucked his hips against her - against her bare pussy, staining the front of his pants wet already - as if possessed, as if he could not help himself. He felt himself spill into his pants, pleasure overtaking his body, totally outside his control.

He stilled against her. 

That wasn’t the plan. He’d ruined it.

Byleth rubbed her palms gently up and down his back. “Is everything alright?” she asked, tentatively. She didn’t know why he had so suddenly stopped moving.

He lifts himself up, color high in his cheeks, and sat back on his heels. Byleth propped herself up on one elbow and looked down. She saw the incriminating wet spot across the front of his pajama pants, and after a moment, her brain caught up with her.

“Ah,” she said, and Felix turned his head to the side, avoiding eye contact. “Oh, hey, it’s okay.” Byleth too sat up, placing one hand under his chin, but he resisted her attempt to make him look at her.

“I ruined it,” Felix muttered, and the misery in his voice was so out of proportion to the situation at hand that Byleth could not stop herself from laughing. Felix snapped his gaze to her, offended, and then clambered from the bed, disentangling himself from between her legs. 

“No, I’m sorry, wait. Felix! Wait.” Byleth scrambled after him, grabbing his hand and pulling until he stopped. He still did not look at her, and she could see the tips of his ears were red. Byleth moved to his front, and pressed her body against his, tucking her head under his chin. She spoke softly, so he had to strain to hear. 

“I don’t think you know,” she began, “how it feels to know that...” Byleth stalled, searching for her words. “How it makes me feel, how good, to know that you want me so badly.” She swallowed. “Please don’t be embarrassed. The look on your face when you touched me, it makes me feel mad. I feel hot now just remembering it.”

Felix laid his cheek against the crown of her head. He murmured, “I barely even got to touch you.”

“There’s still time,” she said, her cheeks burning. “I think it’s bad etiquette to finish yourself and leave your woman wanting, you know.” She felt a throb between her legs and pressed them close together, trying to stymie her desire.

Felix noticed her movement and pulled back slightly, examining her face. “Is that so?” A blush still graced his cheeks, but he seemed determined to ignore it. 

“Just something I’ve heard,” Byleth replied, and she grabbed Felix’s hand in her own. Watching his face closely, she guided his hand beneath the hem of her dress and to her slick folds. Felix sucked in a breath, his fingers tentatively exploring. Byleth closed her eyes and enjoyed the sensation. Her body jolted when he brushed her clit, and he momentarily stilled before stroking with more purpose in the same area. 

It felt _good_, his nimble fingers touching her in her most sensitive place. But the angle was wrong, and his movements were uncertain. 

“Cone here,” Byleth murmured, and stepped backward toward the bed. She saw the wetness - her wetness - on his fingers as he followed her, and it sent an illicit thrill throughout her body. Byleth tugged his arm toward the bed. “Sit up against the wall here,” she instructed him. 

Felix didn’t move. “Why?” He demanded. He moved to touch her again - he wanted to draw more moans from her, wanted to learn what she liked and what he liked and what would make her squirm against him in pleasing ways. Byleth dodged his hand and pushed his shoulder, saying again, “Just sit!”

He sat. 

Byleth stood still in front of him for just a moment, and then she reached down to the hem of her dress and pulled it quickly up, over her head, and off. She watched Felix’s jaw drop. His eyes roved hungrily over her body, and she licked her lips, feeling somewhat self-conscious. She was strong, and very physically capable - she was proud of her body. But it wasn’t every day someone saw you naked for the first time.

“Can I... touch you? Please?” Felix’s voice came out slightly strained, and she grinned. 

“I want you to touch me very badly,” she said. “But I’m going to help you do it right.” 

He made a strangled noise. Then, indignantly, added, “I thought you said you weren’t experienced!”

“Not with other people.” Byleth climbed into the bed on her knees, kneeling in front of him. He raised one hand to her breast and palmed it, eyes on her face to catalogue her reactions. She closed her eyes and savored the touch for a moment. “But I know how to touch myself. Women are no different from men in that way.”

“Oh,” Felix said. He sounded surprised. He brought his other hand to her breasts and brushed each thumb over a nipple, drawing a moan from Byleth. Her core throbbed, desperate for touch. 

“I very badly want you to make me come, now,” Byleth said, and abruptly turned to sit herself between Felix’s legs. She pressed her back to his chest and rested her head against his shoulder, feeling wisps of his hair tickle her forehead. He pressed a kiss to her lips, surprising her, and then ran his hands down her sides, caressing her stomach and hips.

“Show me how,” he said. His voice was rough, deeper than usual. It seemed she had sufficiently distracted him from his earlier embarrassment.

Byleth placed her hand over his and guided it to her center. Using his fingers, she stroked upward through her slick, wet folds, drawing out pleasure with every movement. She heard him hiss out a breath. He let his fingers be pliant under hers, but it was clear he wanted to take charge and explore her himself.

There would be time for that later. 

Slowly, Byleth used Felix’s fingers to circle closer and closer to her clit. He brought his other hand to cup her breast, stroking her nipple and caressing the smooth skin with care.

“You’re beautiful,” he muttered. She opened her eyes to look up at him. Even from a sideways angle, she could tell he was very aroused. His gaze was heavy and lidded, his eyes flicking between his hand on her breast and his fingers - guided by her own - now stroking her clit in a steady rhythm. 

Pleasure was building rapidly in Byleth’s body. The sensations were far too much to handle for long, Felix’s long, sensuous fingers roughened from a lifetime of sword fighting. Each drag over her clitoris sent her closer to the edge; each circle of his thumb on her nipple added a pleasant tingle. She didn’t try to suppress the moans he drew from her, small breathy inhalations turning into drawn-out sounds she might have otherwise been embarrassed about. But the way he looked at her chased all negative feelings away.

“Felix,” she said, but it came out high-pitched, more like she was begging than anything.

“Yeah?” His own voice sounded strained, as if he was holding back.

“I’m coming,” she whispered, and then she was. She coaxed Felix’s fingers over her clit to press and stroke her through her orgasm, her body shaking against his. His arm around her rib cage tightened, holding her through it. Pleasure cascaded through her, each wave rendering her more helpless until she sagged against Felix, her hand dropping to the side. 

Felix wiped his fingers on the bedspread, then wrapped both arms around her torso. He held her against him and they sat that way, in silence, for several minutes. 

“That was good,” Felix finally declared. “Not what I planned on, but I liked how it ended.”

Byleth smiled. She didn’t think he realized how very endearing he could be, even when prickly. She reached up and patted him on the cheek, two times.

“There’s always next time,” she promised.

**Author's Note:**

> I initially wrote this to stand alone, and then I had an idea for a small plot that would turn it into just chaptered smut, and then I had an idea for real plot and I wrote... a couple thousand words of that and couldn't fit this in anymore, so now it's back to standing alone. I might come back and put more smut in that doesn't fit with the other stuff, but no guarantee. Depends how long Felix keeps his claws in me!!


End file.
